IR thermographic investigation of nucleate pool boiling at high heat flux

2016 ◽  
Vol 61 ◽  
pp. 127-139 ◽  
Author(s):  
Jure Petkovsek ◽  
Yi Heng ◽  
Matevz Zupancic ◽  
Henrik Gjerkes ◽  
Franc Cimerman ◽  
...  
Keyword(s):  
Heat Flux ◽  
Pool Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Nucleate Pool Boiling ◽  
Thermographic Investigation

A FRACTAL MODEL FOR NUCLEATE POOL BOILING OF NANOFLUIDS AT HIGH HEAT FLUX INCLUDING CHF

Fractals ◽  
2010 ◽  
Vol 18 (04) ◽  
pp. 409-415 ◽  
Author(s):  
BOQI XIAO ◽  
SONGHUA GAO ◽  
LINGXIA CHEN
Keyword(s):  
Heat Flux ◽  
Volume Fraction ◽  
Pool Boiling ◽  
High Heat ◽  
Fractal Model ◽  
High Heat Flux ◽  
Nucleate Pool Boiling ◽  
Empirical Constant ◽  
Nucleation Sites ◽  
Proposed Model

A fractal model for nucleate pool boiling of nanofluids at high heat flux and critical heat flux (CHF) is developed based on the fractal distribution of nanoparticles and nucleation sites on boiling surfaces in this paper. The formula of calculating high heat flux and CHF for nanofluids in nucleate pool boiling is given by taking into account heat convection between nanoparticles and liquids due to the Brownian motion of nanoparticles in fluids. The proposed model is expressed as a function of temperature of nanofluids, the effective thermal conductivity of nanofluids, the average size of nanoparticles, the fractal dimension of nanoparticles and nucleation sites, the nanoparticles volume fraction of suspension, and physical properties of fluids. No additional/new empirical constant is introduced in this fractal model. An agreement between the proposed model predictions and experimental data is found. The validity of the fractal model for nucleate pool boiling of nanofluids at high heat flux and CHF is thus verified.

scholarly journals Predicting Conduction Heat Flux through Macrolayer in Nucleate Pool Boiling

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3893
Author(s):  
Mohd Danish ◽  
Mohammed K. Al Mesfer ◽  
Khursheed B. Ansari ◽  
Mudassir Hasan ◽  
Abdelfattah Amari ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Current Model ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Nucleate Pool Boiling ◽  
Conduction Heat Transfer ◽  
Wall Superheat

In the current work, the heat flux in nucleate pool boiling has been predicted using the macrolayer and latent heat evaporation model. The wall superheat (ΔT) and macrolayer thickness (δ) are the parameters considered for predicting the heat flux. The influence of operating parameters on instantaneous conduction heat flux and average heat flux across the macrolayer are investigated. A comparison of the findings of current model with Bhat’s decreasing macrolayer model revealed a close agreement under the nucleate pool boiling condition at high heat flux. It is suggested that conduction heat transfer strongly rely on macrolayer thickness and wall superheat. The wall superheat and macrolayer thickness is found to significantly contribute to conduction heat transfer. The predicted results closely agree with the findings of Bhat’s decreasing macrolayer model for higher values of wall superheat signifying the nucleate boiling. The predicted results of the proposed model and Bhat’s existing model are validated by the experimental data. The findings also endorse the claim that predominant mode of heat transfer from heater surface to boiling liquid is the conduction across the macrolayer at the significantly high heat flux region of nucleate boiling.

scholarly journals Developing a Mathematical Model for Nucleate Boiling Regime at High Heat Flux

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 726
Author(s):  
Mohd Danish ◽  
Mohammed Al Mesfer
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Close Agreement ◽  
Current Model ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Nucleate Pool Boiling ◽  
Wall Superheat

A mathematical model has been developed for heat exchange in nucleate boiling at high flux applying an energy balance on a macrolayer. The wall superheat, macrolayer thickness, and time are the parameters considered for predicting the heat flux. The influence of the wall superheat and macrolayer thickness on average heat flux has been predicted. The outcomes of the current model have been compared with Bhat’s constant macrolayer model, and it was found that these models are in close agreement corresponding to the nucleate pool boiling regime. It was concluded that the wall superheat and macrolayer thickness contributed significantly to conduction heat transfer. The average conduction heat fluxes predicted by the current model and by Bhat’s model are in close agreement for a thinner macrolayer of approximately 50 µm. For higher values of the wall superheat, which corresponds to the nucleate pool boiling condition, the predicted results strongly agree with the results of Bhat’s model. The findings also validate the claim that conduction across the macrolayer accounts for the main heat transfer mode from the heater surface to boiling liquid at high heat flux in nucleate pool boiling.

Role of macrolayer evaporation in pool boiling at high heat flux

1986 ◽  
Vol 29 (12) ◽  
pp. 1953-1961 ◽  
Author(s):  
A.M. Bhat ◽  
J.S. Saini ◽  
R. Prakash
Keyword(s):  
Heat Flux ◽  
Pool Boiling ◽  
High Heat ◽  
High Heat Flux

Observations of the Critical Heat Flux Process During Pool Boiling of FC-72

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
J. Jung ◽  
S. J. Kim ◽  
J. Kim
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Pool Boiling ◽  
High Heat ◽  
Line Length ◽  
Boiling Curve ◽  
High Heat Flux ◽  
Transfer Coefficients ◽  
Ir Camera

Experimental work was undertaken to investigate the process by which pool-boiling critical heat flux (CHF) occurs using an IR camera to measure the local temperature and heat transfer coefficients on a heated silicon surface. The wetted area fraction (WF), the contact line length density (CLD), the frequency between dryout events, the lifetime of the dry patches, the speed of the advancing and receding contact lines, the dry patch size distribution on the surface, and the heat transfer from the liquid-covered areas were measured throughout the boiling curve. Quantitative analysis of this data at high heat flux and transition through CHF revealed that the boiling curve can simply be obtained by weighting the heat flux from the liquid-covered areas by WF. CHF mechanisms proposed in the literature were evaluated against the observations.

Sign in / Sign up

Export Citation Format

Share Document